User Defined Coordinate Systems

The User Defined System dialog allows you to define your own coordinate systems and save the origin and orientation of these systems as a Session file or a Report.

Saving to a session file is only through x, y, z coordinates of the origin and three direction cosine vectors for the orientation.

Create a User Defined Coordinate System

All user defined coordinate systems are static (or fixed).
  1. From the Results Browser, right-click and select Create > System.
  2. From the User Defined System dialog, select one of the available coordinate systems.
    • Rectangular (X, Y, Z)
    • Cylindrical (R-Theta-Z)
    • Spherical (R-Theta-Phi)
    You are able to make changes to the coordinate system Type (Rectangular, Cylindrical, Spherical) after it has been created, however once a system exists you are no longer able to make changes to the location of the coordinate system.
  3. Select a method.
  4. Define nodes.
    Option Description
    By node Under Pick nodes, specify a minimum of three nodes to define the orientation of the system.

    HyperLife will automatically provide the x, y, z positions (coordinates) of the nodes at the time of definition. For the Linear or Modal animation modes, the undeformed position (model location) of nodes is considered in defining the system. For the Transient animation mode, the deformed position (current location at the time step) is considered. Once a coordinate system is created, the orientation remains fixed independent of how the model deforms.

    Note: Scaling does not affect the position of the nodes/points. The unscaled coordinates of the current node/point positions are used when defining nodes/points.

    User defined systems definitions are updated for Linear and Modal animation modes. The undeformed position (model location) of nodes is considered in defining the system. For Transient animation mode, the deformed position (current location at the time step) is considered. Once a coordinate system is created, the orientation remains fixed independent of how the model deforms.

    1. Click the Origin input collector and use the Select by ID dialog to specify your desired nodes.
    2. Click the X Axis input collector and use the Select by ID dialog to specify your desired nodes.
    3. Click the XY Plane input collector and use the Select by ID dialog to specify your desired nodes.
    By coordinates Under Enter Co-ordinates, specify three nodes to define the orientation of the system.
    1. Define the Origin of the system.
    2. Define the local X-Axis (or R-Axis for Cylindrical or Spherical systems).
    3. Define the X-Y Plane (or the R-Theta Plane for Cylindrical or Spherical systems).
    Circle center Under Pick 3 circle circumference nodes, specify three nodes lying on the circumference of the circle to define a coordinate system at the circle center.

    The origin of the system will be the circle center, and the x-axis of the system will defined along the vector between the circle center and the first selected node.

    Note: If a circle center could not computed using the three selected nodes (for example collinear nodes), then a default system will be created. The axes of this default system will align along the global axes.
    1. Click the Node 1 input collector and use the Select by ID dialog to specify your desired nodes.
    2. Click the Node 2 input collector and use the Select by ID dialog to specify your desired nodes.
    3. Click the Node 3 input collector and use the Select by ID dialog to specify your desired nodes.
  5. Click OK to apply the settings/changes and exit the dialog.

Edit a User Defined Coordinate System

Use the User Defined System dialog to review and edit (or redefine) user defined coordinate systems.
  1. From the Results Browser, right-click on one of the existing systems and select Edit from the context menu.
    Restriction: Only user defined coordinate systems can be modified or deleted. Coordinate systems from the input deck cannot be modified or deleted, they can only be reviewed.
    The User Defined System dialog is displayed.
  2. Edit or modify the definition of the system by changing the system 'type' or redefine the system by selecting new nodes.
    Note: The coordinates are not retained.
    The coordinates of the nodes are internally updated whenever you update the node IDs.
    • You therefore do not need to remember the node IDs, only their positions at the time of creation/updating of the Coordinate System is modified.
    • To modify the coordinate system, you simply need to provide new node IDs. New node IDs automatically get converted to x, y, z positions.
    • Node positions can change while in transient mode, however the Coordinate System will not change until it is updated.

    No scaling of deformation contributes to the changing of position of the nodes. Unscaled node coordinates at the time of Coordinate System creation are used.

  3. Click OK to apply the settings/changes and exit the dialog.

Delete a User Defined Coordinate System

From the Results Browser, right-click on one of the existing systems and select Delete from the context menu.
Note: Only user defined coordinate systems can be modified or deleted. Coordinate systems from the input deck cannot be modified or deleted, they can only be reviewed.